1. Field of the Invention
This invention pertains to boating, and more particularly to techniques for safely anchoring or mooring a plurality of boats in nonoverlapping and noninterfering locations in an anchorage. This invention also relates to a device for displaying and indicating to other vessels the relevant characteristics of a moored or anchored boat.
2. Prior Art
There are three principal ways to secure a boat when not in use, namely, docking the boat at a slip, mooring the boat in a generally protected area, or dropping anchor in open water. Several considerations come into play when anchoring or mooring a boat. For example, in crowded anchorages, it is desirable for larger boats to anchor in deeper water farther from shore, leaving shallow, sheltered spots for the smaller boats. This is not only an efficient use of available space, but also reduces the effects of waves on the smaller boats. Another, principal consideration in selecting a safe anchorage or mooring site is a determination of the amount of anchor line, also known as anchor rode, to pay out. Not only is this an important factor in the holding power of the anchor, it also determines the size of the circle circumscribed by the boat as it swings about its anchor with changes in tide, wind direction, etc.
Since, for a given anchor rode, the size of the circle circumscribed by the boat about its mooring is also dependent on water depth, the length of anchor rode payed out between the bow and the tackle is usually expressed in terms of "scope", which is defined as the ratio of the length of the anchor rode divided by the distance from the bow to the bottom. So, for example, in 20 feet of water, with a bow 5 feet off the water, 150 feet of anchor rode would result in a scope ratio of six-to-one. Typically, scope ratios for combination rope and chain anchor rodes range from five-to-one to ten-to-one, with seven or eight-to-one being common in average conditions. For safety and uniformity, scope ratios are calculated at high tide.
Because the scope ratio determines the size of the circle the boat makes about its anchor, failure to select a proper scope ratio, especially in a crowded anchorage, can be disastrous. For example, if a boat selects a mooring or anchor site a few boat lengths astern of a previously moored or anchored boat, which is generally accepted as a safe distance, the second boat may nevertheless swing into the first if the scope ratio of either boat is too high or too low. Accordingly, it is important for the second boat to be aware of the scope ratio of the first boat when selecting its own scope ratio and mooring or anchoring location.
When a stiff breeze is blowing, a reasonably skilled skipper can determine the scope ratio of anchored boats by the angle their anchor lines make with the water, i.e., the more acute the angle between the anchor line and the water, the higher the scope ratio. However, in light air, a boat can drift over its anchor, presenting the appearance of a low scope ratio when, in fact, the scope ratio may be higher. This situation is complicated by the fact that the scope ratio for all-chain rodes should be from about three-to-one to five-to-one whereas, as noted, the scope ratio for combination rope and chain anchor rodes generally ranges from about five-to-one to about ten-to-one.
The desired scope ratio for one's own boat can be readily attained by labeling the anchor rode at regular intervals, as with ribbons, plastic tags, etc. For example, if the anchor rode is marked every 6 feet, the skipper can readily determine the amount of anchor rode to pay out to achieve a desired scope ratio if the water depth and bow height are known. Thus, for a water depth of 10 feet and a bow height of 5 feet, a scope ratio of six-to-one is achieved by paying out 90 feet of anchor rode, or 15 ribbons.
Ideally, all boats at an anchorage should be moored or anchored with about the same scope ratio but, as noted, for example, in the article "Proper Etiquette In The Anchorage", Sail Magazine, October, 1987, "this hardly ever happens". Oftentimes, skippers put out abnormally long or short anchor lines. Also, for the reasons noted above, it is not always easy or possible to determine the scope ratio of other boats by observing the angles their anchor lines make with the water line. Since the fault for any collisions occurring between two boats during swinging will generally be attributed to the second vessel to anchor or moor, the first having the equivalent of squatter's rights, it is all the more important that boats coming into an occupied anchorage be able to properly assess the scope ratios of boats already anchored or moored so that they can select a safe location in which to anchor or moor. Nevertheless, and as noted, this is not always easy.
Accordingly, it is an object of the present invention to provide a method whereby incoming boats will be able to readily determine the scope ratios of previously anchored or moored boats.